For semiconductor manufacturing, such as the wafer fabrication process, countless efforts are paid to achieve strict process control in all aspects including the product, process, production device, etc. The process flow for one particular product is composed of several processing paths, which starts from one end to the other end. There are certified processing devices located at the ends of a processing path. In most of the cases, each of the processing paths shall be verified before being released for production, i.e., each of the processing devices has to be certified with testing data collected from specimens processed along the processing path. If there is only one specific machine certified for one particular production at one end of a particular path, the availability of the specific machine will be critical to the productivity of the particular production. In case the specific machine is busy or repaired, the particular production will be put on hold if there is no alternative processing path.
Many of the processing devices at different ends of a processing path are different types of machines but somehow correlated in terms of a processing character. For example, a typical processing path in wafer fabrication process flow is from lithography to etching, wherein steppers and etcher are utilized at the processing steps of lithography and etching respectively, and the etching effect to a critical dimension at a particular field of the wafer can be compensated by pre-adjusting dose energy at the particular field of the wafer. According to suggestions from vendors of the processing devices, the uniformity issue due to etcher bias pattern can be improved by corrections at the dose energy map, which is employed at the lithograph process when a stepper is managed to choose dose energies to be applied at different areas (fields) of a wafer. Since the bias pattern of the each etcher is unique, the energy dose map utilized at the stepper should be based on the etcher to be selected for the subsequent etching process. Once a particular layer of a wafer is processed with a particular dose energy map, which is designed specifically for an etcher, the processing path for the wafer is then determined so that the wafer cannot be processed by any other etcher. Accordingly, there is a need to solve the abovementioned deficiencies/problems.